This invention relates generally to processes and apparatus for disinfecting soft contact lenses and, more particularly, to processes and apparatus for disinfecting soft contact lenses by heat disinfection.
In caring for hydrophilic gel (soft) contact lenses, attention must be directed toward, among other things, maintaining lens hydration and protecting the lenses from pathogens. Exposure of soft contact lenses to heat or to the action of soaking solutions are the techniques used to provide the disinfection necessary to protect soft contact lenses from pathogens.
Disinfecting lenses by soaking in germicidal solutions is a two step process which includes soaking the lenses in the solution until the lens is disinfected, and then rinsing the lenses with a rinsing solution prior to insertion. Typically, lenses are stored in a germicidal solution, such as one that derives its germicidal activity from thimerosal or chlorhexidine, for at least four hours and then are rinsed in a saline solution. Such techniques are time consuming, require the user to keep different solutions on hand, and risk eye irritation should the disinfecting solution not be adequately rinsed from the lenses.
For heat disinfection, it is generally necessary to heat soft contact lenses to a temperature of 80.degree. C. for at least 10 minutes. To insure lens hydration, the gel lenses are immersed in saline solution in their storage case which is then placed within a boiling unit. Although gel lenses can be disinfected in a shorter time by heat than by soaking, conventional heat disinfection techniques require a separate heating unit which adds to the expense of lens care. Moreover, in practice, heat disinfection of lenses is a relatively time-consuming procedure which necessitates that the wearer uses an alternate pair of lenses, or eyeglasses, while disinfection proceeds.